Systems and methods for satellite noise and interference calibration using terminal measurements

ABSTRACT

Systems and methods are provided for satellite noise and interference calibration using satellite terminal measurements. In one implementation, a method includes partitioning a satellite network into a first partition including a plurality of terminals and a plurality of inroute frequency channels (IFCs); instructing the plurality of terminals of the partition to measure the SINR of the plurality of IFCs; processing the plurality of SINR measurements to compute normalized IFC measurements for each of the plurality of terminals; processing the normalized IFC measurements for each terminal to compute final calibrated IFC SINR offsets for each IFC of the partition; and normalizing the final calibrated IFC SINR offsets with respect to a lowest SINR offset IFC. The normalized final calibration offsets may be made available to each of the satellite terminals. During subsequent operation, the satellite terminals may consider the amount of interference present in an IFC before switching to the channel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims the benefit of U.S.patent application Ser. No. 14/590,776, filed Jan. 6, 2015, which issuedas U.S. Pat. No. 9,749,067 on Aug. 29, 2017.

TECHNICAL FIELD

The present disclosure relates generally to satellite networks. Moreparticularly, some embodiments of the present disclosure are directedtoward systems and methods for satellite noise and interferencecalibration.

BACKGROUND

Modern satellite communication systems provide a robust and reliableinfrastructure to distribute voice, data, and video signals for globalexchange and broadcast of information. These satellite communicationsystems have emerged as a viable option to terrestrial communicationsystems for carrying data traffic such as Internet traffic. A typicalsatellite Internet system comprises subscriber terminals, a satellite, aground station, and connectivity to the internet. Communication in sucha system occurs along two links: 1) an uplink from a subscriber terminalto the satellite to the ground station to the gateway to the internet;and 2) a downlink from the internet to the gateway to the ground stationto the satellite to the subscriber terminal.

The signal quality of a link (up or down) is determined by the signal tointerference-plus-noise ratio (SINR) of the link. The higher the SINR,the higher the symbol rate that can be utilized and the more efficientthe error correcting codes that can be used, resulting in higherthroughput speeds. Generally, for a dynamic variable rate system, eachcombination of symbol rate and error correcting code rate pair (SYMCOD)will be associated with a SINR operating range. This SINR range is setby the bit error rate (BER) or packet error rate (PER). Specifying a BERor PER will determine at what SINR that combination pair can operate. Ifa link has enough excess SINR, it may try to operate at a higher SYMCOD.However, if a link has a SINR too low for the SYMCOD it operates at,high PER will result and degrade the throughput speeds and latency ofthat internet link.

The SINR is determined by the ratio of the signal power divided by thecombination of the thermal noise power and the power level of othersources of interference. The thermal noise is a function of thetemperature of the receiving hardware, and is typically flat over thefrequency operating range. By contrast, other sources of interferencegenerally are not flat and may vary from frequency to frequency. Theseother sources may include adjacent satellites operating at the samefrequency bands, other subscriber terminals with the local satelliteoperating at the same or adjacent frequencies, or other systemcomponents that operate at the same or adjacent frequencies.

For inroute transmissions from a subscriber terminal to the satellite,the uplink frequency band is partitioned into subband channels known asinroute frequency channels (IFC). Generally, each IFC operates aspecific symbol rate (e.g., 1.024 Msps, 2.048 Msps, 4.096 Msps, etc.)During operation, a subscriber terminal may jump from one IFC to anotherfollowing an ALOHA messaging scheme. For example, a subscriber terminalmay jump to an IFC operating at a higher SYMCOD if it determines thereis enough of a margin to do so while operating at an acceptable PER onthe new channel.

However, because each IFC operates at a different frequency, the SINR ofeach channel may be different. If the subscriber terminal does not knowthe SINR of the target IFC in advance, it only accounts for the SYMCODof the target IFC in determining whether there is enough margin to makethe jump. Where the SINR of the target IFC is lower than SINR (i.e.higher interference) of the original channel, the subscriber terminalmay operate at too high a PER when it jumps to the target IFC.Conversely, a terminal may fail to consider its ability to jump to anIFC operating at a higher SINR (i.e. less interference) and higherSYMCOD.

This IFC transitioning problem manifests itself in various settings. Forexample, in satellite systems having a rain adaptation feature, aterminal reduces the SYMCOD whenever a rain fade is detected to accountfor the lower SINR caused by the attenuation in signal power. Forexample, a terminal operating at a 4.096 Msps IFC may drop down to a1.024 Msps or lower IFC. As the terminal transits channels, it is vitalthat the SINR of the transit IFC be known to allow correct IFCallocation. Otherwise, packet loss may occur.

As another example, when a terminal operates at an initial SINR withenough SINR margin to operate at a higher SYMCOD, it will try to operateat a higher SYMCOD by switching to a different IFC. However, if thehigher SYMCOD target IFC has a lower SINR (i.e. higher interferencelevel), the SINR margin may be insufficient to operate at the higherSYMCOD. When the terminal switches to the target IFC and sees the highpacket loss and low SINR, the terminal switches to a lower SYMCOD ratechannel. The terminal again sees excess SINR and this problemiteratively repeats itself.

Accordingly, it is important for a terminal to account for thedifference in SINR of the channels (in addition to SYMCOD) beforedeciding to change channels.

The conventional method of addressing this problem relies on manual useof a spectrum analyzer at the gateway. Under this conventional approach,the spectrum analyzer is used to measure the spectrum of each IFCmanually, and this is followed by manually post processing each of themeasured spectrums in attempt to determine the margins for every IFC forevery group of inroutes. The determined margins are entered into acalibration table that may be made available to the terminals.

The conventional spectrum analyzer method has many drawbacks. First, itis a cumbersome and manual-labor intensive process, particularly whenmeasuring all satellite bands, spot beams, and polarizations. Further,the method is limited to measuring the spectrum of a small subset ofterminals. Additionally, the conventional method requires that all theuser terminals operating in a band be barred from transmission to havean accurate representation of the noise and interference present in theband that is being calibrated, thereby preventing the user terminalsfrom accessing the internet. Further, still, the process is ill-suitedfor the frequent system recalibrations desired due to 1) the dynamicnature of interference caused by sources other than thermal noise, and2) changes in the satellite system configuration.

SUMMARY

Systems and methods are provided in various embodiments for satellitenoise and interference calibration using terminal measurements. In oneembodiment, a method includes: instructing a satellite terminal tomeasure the signal to interference-plus-noise ratio (SINR) of an inroutefrequency channel (IFC); receiving the SINR measurement corresponding tothe IFC; and determining a SINR offset calibration for the IFC based onthe SINR measurement. In a particular implementation of this embodiment,the method may further include instructing a second satellite terminalto measure the SINR of the IFC; receiving the second SINR measurementcorresponding to the IFC; determining the SINR offset calibration forthe IFC based on the second SINR measurement; and transmitting the SINRoffset calibration to the satellite terminals.

In accordance with another embodiment of the technology disclosedherein, a method includes: partitioning a satellite network into a firstpartition comprising a plurality of terminals and a plurality of inroutefrequency channels (IFCs); selecting terminals from the first partitionto target one or more of the plurality of IFCs for SINR measurement; anddirecting each of the selected terminals from the first partition tomeasure the SINR of the targeted IFCs. In an implementation of thisembodiment, the method may further include partitioning the satellitenetwork into a second partition comprising a second plurality ofterminals and a second plurality of IFCs; selecting terminals from thesecond partition to target one or more of the second plurality of IFCsfor SINR measurement; and directing each of the selected terminals fromthe second partition to measure the SINR of the targeted IFCs of thesecond plurality of IFC.

In accordance with another embodiment of the technology disclosedherein, a system includes: a satellite comprising an inroute channel andan outroute channel; and a satellite gateway (SGW) configured to:instruct a plurality of terminals over the outroute channel to measurethe SINR of a plurality of IFC corresponding to a satellite networkpartition; and receive the SINR measurements over the inroute channel.In an implementation of this embodiment, the SGW is further configuredto determine SINR offset calibrations for the plurality of IFC based onthe received SINR measurements.

In accordance with yet another embodiment of the technology disclosedherein, a methods includes: partitioning a satellite network into apartition comprising a plurality of terminals and a plurality of inroutefrequency channels (IFCs); instructing the plurality of terminals tomeasure the SINR of the plurality of IFCs; processing the plurality ofSINR measurements to compute normalized IFC measurements for each of theplurality of terminals; and processing the normalized IFC measurementsfor each terminal to compute final calibrated IFC SINR offsets for eachIFC of the partition. In an implementation of this embodiment, themethod further includes normalizing the final calibrated IFC SINRoffsets with respect to a lowest SINR offset IFC.

In accordance with yet another embodiment of the technology disclosedherein, a system includes: one or more processors; and one or morenon-transitory computer-readable mediums operatively coupled to at leastone of the one or more processors and having instructions stored thereonthat, when executed by at least one of the one or more processors, causeat least one of the one or more processors to: compute initialstatistics for a plurality of inroute frequency channels (IFCs) SINRmeasurements made by a plurality of terminals; normalize the SINRmeasurements for each terminal; and determine clear channels of theplurality of IFC based on the normalized SINR measurements. In animplementation of this embodiment, the instructions when executed by atleast one of the one or more processors, further cause at least one ofthe one or more processors to determine final calibrated IFC SINRoffsets for each of the plurality of IFCs.

Other features and aspects of the disclosure will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate, by way of example, the featuresin accordance with various embodiments. The summary is not intended tolimit the scope of the invention, which is defined solely by the claimsattached hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The technology disclosed herein, in accordance with one or more variousembodiments, is described in detail with reference to the followingfigures. The drawings are provided for purposes of illustration only andmerely depict typical or example embodiments of the disclosedtechnology. These drawings are provided to facilitate the reader'sunderstanding of the disclosed technology and shall not be consideredlimiting of the breadth, scope, or applicability thereof. It should benoted that for clarity and ease of illustration these drawings are notnecessarily made to scale.

FIG. 1 illustrates an example multi-satellite data transmission systemin which various embodiments of the disclosure may be implemented.

FIG. 2 is an operational flow diagram illustrating an example method forautomatically determining calibrated SINR offsets for a plurality of IFCusing terminal measurements of the SINR.

FIG. 3 is an operational flow diagram illustrating an example method ofselecting and using the terminals to measure the SINR of different IFCas described in FIG. 2.

FIG. 4A is an operational flow diagram illustrating an example method ofdetermining a normalized set of SINR offset calibrations for a partitionbased on SINR measurements performed by a set of terminals of thepartition.

FIG. 4B is an operational flow diagram illustrating an example method ofprocessing IFC measurements made by each terminal to compute normalizedIFC measurements.

FIG. 4C is an operational flow diagram illustrating an example method ofprocessing normalized IFC measurements of each terminal of a partitionto compute final calibrated IFC SINR offsets for each channel of thepartition.

FIG. 5 is a table illustrating a particular implementation of operationsof the method of FIG. 4.

FIG. 6 is another table illustrating a particular implementation ofoperations of the method of FIG. 4.

FIG. 7 is another table illustrating a particular implementation ofoperations of the method of FIG. 4.

FIG. 8 is a plot illustrating an example inroute calibration mapping fora satellite beam created by applying the methods disclosed herein.

FIG. 9 is another plot illustrating another example calibration mappingfor another satellite beam created by applying the methods disclosedherein.

FIG. 10 illustrates an example computing module that may be used inimplementing features of various embodiments.

FIG. 11 illustrates an example chip set that can be utilized inimplementing architectures and methods for dynamic bandwidth allocationin accordance with various embodiments.

The figures are not intended to be exhaustive or to limit the inventionto the precise form disclosed. It should be understood that theinvention can be practiced with modification and alteration, and thatthe disclosed technology be limited only by the claims and theequivalents thereof.

DETAILED DESCRIPTION

Various embodiments of the systems and methods disclosed herein providetechniques for a terminal in a satellite network system to account forthe SINR offset when switching from one IFC to another IFC. Certain ofthese techniques may include using a plurality of terminals of thesatellite network system to perform a ranging process that automaticallymeasures the SINR of a different IFC. From these measurements, anormalized SINR offset calibration may be determined for each channel.The normalized calibration offsets may be made available to each of theterminals. During subsequent operation, the terminals may consider theamount of interference present in an IFC before switching to thechannel.

As noted above, for inroute transmissions from a terminal to asatellite, the uplink frequency band is partitioned into subbandchannels known as inroute frequency channels (IFC). Because each IFCoperates at a different frequency, the interference levels (andtherefore SINR) of each channel may be different. Accordingly, as aterminal switches channels, the SINR offset is an importantconsideration for determining whether the terminal will operate at anacceptable quality of service. In various embodiments, the disclosedtechnique may be implemented in any single or multi-satellite network,with any number of spot beams and terminal groups, to automaticallycalculate the SINR offset of the IFC of the satellite network.

The disclosed technique provides numerous benefits over conventionalmethods of determining the SINR offsets of the IFC. First, the disclosedtechnique adds no additional cost to operating the satellite network asit utilizes available terminals to measure the SINR of the IFC. Second,the disclosed technique automates the process of measuring the SINR ofthe IFC by utilizing the available terminals' ranging capabilities.Third, the disclosed technique may be used to gather SINR data rapidlyfor all IFC for a large number terminals, thereby insuring a reliablesample size of measurements. Finally, implementation of the disclosedtechnique adds no noticeable service degradation for the subscribers ofthe terminals.

FIG. 1 illustrates an example satellite network 10 in which elementsinvolved in inroute communications/traffic are described. Satellitenetwork 10 in this example can include multiple satellites 12 a and 12b, remote terminals 14 a-14 f, radio frequency (RF) terminals 16 a and16 b, multiple inroute group managers (IGMs) 18 a, 18 b, . . . 18 n,satellite gateway (SGW) 19, and IP gateways (IPGWs) 20. The satellitenetwork may be a shared access broadband network. Other types of sharedaccess networks may include, for example, wireless networks such as4^(th) Generation Long Term Evolution (4G LTE) and WiMAX networks, whichmay include terminals other than Very Small Aperture Terminals (VSATs),such as cellular and WiFi equipped devices.

Feeder links may carry data between RF terminals 16 a and 16 b andsatellites 12 a and 12 b, and may include: forward uplinks 23 a and 27 afor transmitting data from RF terminals 16 a and 16 b to satellites 12 aand 12 b, respectively; and return downlinks 25 a and 29 a fortransmitting data from satellites 12 a and 12 b, respectively, to RFterminals 16 a and 16 b. User links may carry data between satellites 12a and 12 b and remote terminals 14 a-14 f, and may include: returnuplinks 25 b and 29 b for transmitting data from remote terminals 14a-14 f to satellites 12 a and 12 b, respectively; and forward downlinks23 b and 27 b for transmitting data from satellites 12 a and 12 b,respectively, to remote terminals 14 a-14 f Forward uplinks 23 a, 27 aand forward downlinks 23 b, 27 b may form an outroute, and returnuplinks 25 b, 29 b and return downlinks 25 a, 29 a may form an inroute.SGW 19 may include high capacity earth stations with connectivity toground telecommunications infrastructure. SGW 19 may be communicativelyconnected to RF terminals 16 a and 16 b. RF terminals 16 a and 16 b maybe the physical equipment responsible for sending and receiving signalsto and from satellites 12 a and 12 b, respectively, and may provide airinterfaces for SGW 19/IPGWs 20.

Satellites 12 a and 12 b may be any suitable communications satellites.For example, satellites 12 a and 12 b may be bent-pipe designgeostationary satellites, which can accommodate innovations andvariations in transmission parameters, operating in the Ka-band,Ku-band, or C-band. Satellites 12 a and 12 b may use one or more spotbeams as well as frequency and polarization reuse to maximize the totalcapacity of satellite network 10. Signals passing through satellites 12a and/or 12 b in the forward direction may be based on the DVB-S2standard (ETSI EN 302 307) using signal constellations up to andincluding at least 32-APSK. The signals intended to pass throughsatellites 12 a and 12 b in the return direction (from terminals 14 a-14f) may be based on the Internet Protocol over Satellite (IPoS) standard(ETSI TS 102 354). Other suitable signal types may also be used ineither direction, including, for example higher data rate variations ofDVB-S2.

IPGWs 20 may be an ingress portion of a local network. IP traffic,including TCP traffic, from the internet may enter an SGW 19 throughIPGWs 20. IPGWs 20 may each include a spoofer, which may acknowledge IPtraffic, including TCP traffic sent to SGW 19. Moreover, SGW 19 may beconnected to an internet through IPGWs 20. IP traffic, including TCPtraffic, from the internet may enter SGW 19 through IPGWs 20. Asillustrated in FIG. 1, multiple IPGWs may be connected to a single IGM.The bandwidth of RF terminals 16 a and 16 b can be shared amongst IPGWs20. At each of IPGWs 20, real-time (RT) and NRT traffic flows may beclassified into different priorities. These traffic flows may beprocessed and multiplexed before being forwarded to priority queues atSGW 19. RT traffic may go directly to an RT priority queue or SGW 19,while NRT traffic flows may be serviced based on the respective priorityand volume. Data may be further packed into DVB-S2 code blocks andstored in a code block buffer before transmission.

Data from an internet intended for remote terminals 14 a-14 f (e.g.,VSATs) may be in the form of IP packets, including TCP packets and UDPpackets, or any other suitable IP packets, and may enter SGW 19 at anyone of IPGWs 20, where the respective spoofer may send an acknowledgmentback to the sender of the IP packets. The IP packets may be processedand multiplexed by SGW 19 along with IP packets from other IPGWs, wherethe IPGWs may or may not have the same service capabilities and relativepriorities. The IP packets may then be transmitted to satellites 12 aand 12 b on forward uplinks 23 a and 27 a using the air interfacesprovided by RF terminals 16 a and 16 b. Satellites 12 a and 12 b maythen transmit the IP packets to the VSATs using forward downlinks 23 band 27 b. Similarly, IP packets may enter the network via the VSATs, beprocessed by the VSATs, and transmitted to satellites 12 a and 12 b onreturn uplinks 25 b and 29 b. Satellites 12 a and 12 b may then sendthese inroute IP packets to the SGW 19/IPGWs 20 using return downlinks25 a and 29 a.

Each of remote terminals 14 a-14 f can be, for example, VSATs and mayconnect to the Internet through satellites 12 a and 12 b and IPGWs20/SGW 19. For example, remote terminal 14 a may be used at a residenceor place of business to provide a user with access to the Internet.VSATs or Mobile Satellite Terminals (MSTs), may be used by end users toaccess the satellite network, and may include a remote satellite dishfor receiving RF signals from and transmitting RF signals to satellite12 a, as well as a satellite modem and other equipment for managing thesending and receiving of data. They may also include one or more remotehosts, which may be computer systems or other electronic devices capableof network communications at a site.

At SGW 19, one or more IGMs can be implemented (IGMs 18 a, 18 b, . . .18 n). These IGMs may be bandwidth controllers running bandwidthallocation algorithms. The IGMs may manage bandwidth of the remoteterminals 14 a-14 f in the form of inroute groups (IGs), based in parton bandwidth demand requests from the remote terminals 14 a-14 f.

For inroute (uplink) transmissions from terminals 14 a-14 f tosatellites 12 a and 12 b, the uplink frequency band of a satellite beammay be split into any number of subband IFC with any number of symbolrates of, for example, 512 ksps, 1 Msps, 2 Msps, 4 Msps, etc. Dependingon operating conditions (e.g. weather, status of terminal, status ofsatellite), a terminal 14 a-14 f may attempt to transmit from one IFC toa target IFC with a same, lower, or higher symbol rate.

Because of the varying interference levels amongst the IFC, the signalquality (i.e. SINR) may vary from one channel to the next. In accordancewith various embodiments, as will be further described below, the SINRoffset of each IFC may be periodically calculated and made available tothe terminals. In these embodiments, a terminal operable to transmit ina frequency transits to an IFC of the band if the SINR offset of the IFCis within an acceptable level. For example, a SINR offset may beacceptable for an IFC with a given SYMCOD if the terminal is able tooperate in the channel below a predetermined packet error rate.

FIG. 2 is an operational flow diagram illustrating an example method 200for automatically determining calibrated SINR offsets for a plurality ofIFC using terminals 14 a-14 f to make measurements of the SINR. Itshould be noted that although method 200 is described with reference toexample multi-satellite data transmission system 10, the disclosedmethod may be implemented in any satellite data transmission systemcomprising any number of satellites, spot beams, polarizations,terminals, terminal groups, and IFCs. It should also be noted thatalthough method 200 is described with reference to a system that haspreviously been calibrated, it may similarly be implemented in a systemthat is being calibrated for the first time.

With reference now to method 200, at decision 202 it is determined thatthe SINR offset calibrations for all or a subset of IFCs need to beupdated. In one embodiment, the SINR offset calibrations areperiodically updated after a predetermined period of time (e.g. 1 day, 2days, 4 days, a week, etc.) has passed since the last calibration. Theperiodic update time may be specified at SGW 19 by an operator ofsatellite system 10 depending on the expected SINR drift rate of theIFC, weather patterns, the positional drift of satellites 12 a or 12 b,and other considerations. In another embodiment, the SINR calibrationsare updated if there have been any changes to the configuration ofsystem 10 such as updates to the equipment of terminals 14 a-14 f,updates to RF terminals 16, the addition of satellites, changes inpolarizations, the addition of outroute or inroute channels utilizingnew frequency bands, conversion of a narrow band to a wideband, etc.

After there is a determination that SINR calibrations will be made, atoperation 204 some or all of the terminals are selected to perform aranging process (one or more multiple times) over some or all of the IFCavailable to them to measure the signal to noise ratio (i.e. SINR) ofeach IFC. In various embodiments, the terminals may be instructed totake these measurements during times that are least likely to degrade asubscriber's terminal service. For example, each terminal may bedirected to measure the SINR of the IFC in the middle of the night (orat some other opportune window) during three separate times. As onehaving ordinary skill in the art will appreciate, the ranging processfor each terminal may be completed in the span of a few seconds orminutes and does not require complete interruption of a terminal'sservice. For example, if a subscriber terminal provides a user Internetaccess for home use, the user may still browse the web even as rangingis performed.

In one embodiment, an IGM 18 a-n of SGW 19 directs one or more ofterminals 14 a-14 f to measure the SINR of the various IFCs. In thisembodiment, the IFC measurements may be transmitted back to IGM 18 a-nfor subsequent calibration by the IGM 18 a-n or other device. In anotherembodiment, multiple IGMS may direct terminals of their respective TG toperform the SINR measurements. In this embodiment, a separate set ofcalibrations may be determined for each TG's set of measurements.

Once the SINR measurements have been made, at operation 206 one or moresets of SINR offset calibrations may be created based on the terminalmeasurements. For example, in one embodiment, a set of SINR measurementsmay be normalized with respect to an IFC channel with the highest SINR(highest signal quality). In this embodiment, further described below,the normalized SINR offsets of the IFC channels may be given withrespect to the highest SINR IFC. Alternatively, in another embodimentthe SINR measurements may be normalized with respect to other referencessuch as, for example, the IFC channel with the lowest SINR (lowestsignal quality).

At operation 208, the SINR offset calibrations are subsequentlytransmitted to the terminals 14 a-f through the outroute links. In oneembodiment, the calibrations are provided to the terminals in a table.In one implementation of this embodiment, for example, a separate SINRoffset calibration table may be provided for each TG. Alternatively, thesame SINR offset calibration table may be provided to all the terminals.In an alternative embodiment, the SINR offset calibrations may bemanually delivered to the terminals using a portable storage drive suchas a flash drive. In further embodiments, still, the terminals 14 a-14 fmay download the SINR offset calibrations from a separate network.

FIG. 3 is an operational flow diagram illustrating an example method 300of selecting the terminals to measure the SINR of different IFC asdescribed in operation 204 of method 200. Prior to directing anyterminals to measure the SINR of the IFC, at operation 302 the satellitenetwork is partitioned. For example, a set of terminals from thesatellite network may be partitioned based on a shared satellite beam, ashared frequency band, a shared TG, and/or shared applicationcharacteristics. At operation 304, a number of terminals from eachpartition are selected to take SINR measurements. The selection of theterminals may depend on parameters such as the whether the terminals areoperating with a clear sky SINR, the number of terminals needed toobtain statistically reliable measurements of SINR, the operationalstatus of the terminal, etc. In one embodiment, terminals that satisfysome or all of these parameters are randomly selected up to a givennumber. In an alternative embodiment, SINR measurements are taken forall operational terminals of a given partition.

As an example, consider the case where a satellite network partition isbased on a frequency band including 20 different channels and a set of100 terminals sharing a common modem. From this partition, a terminal isselected to take SINR measurements if, for example, the terminal isoperating with a satisfactory clear sky SINR and does not have any otheroperational issues. As another example, a satellite network partitionmay be based on a satellite beam covering 50 different channels andincluding a set of 200 terminals sharing similar modems.

At operation 306, the selected terminals are directed to target anynumber of IFCs of their respective band partition and measure the SINRof each targeted IFC (i.e. perform ranging). For example, a giventerminal may be directed to measure the SINR of the IFC by sequentiallytransitioning between the channels in order of increasing or decreasingfrequency. The measurements may be stored at the terminal andsubsequently transmitted in the inroute toward SGW 19 for processing.

In one embodiment, the terminals measure each targeted IFC multipletimes to reduce measurement errors, minimize any local weather conditionthat may affect the SINR measurements, and otherwise generatestatistically reliable measurements. In implementations of thisembodiment, the measurements may be spread over various times. Forexample, a terminal may make a set of 4 IFC SINR measurements at 1 a.m.,2 am, and 3 a.m., and 4 a.m. In this example, taking the measurementsover a period of three hours helps average out any temporal sources oferror. Additionally, any issues related to degradation of a subscriber'sservice are avoided by taking the measurements during the late night(i.e. low usage hours).

As previously described in operation 206 of FIG. 2, after measuring theSINR of the IFC, a set of calibration SINR offsets may be determined. Anexample implementation of this functionality is described with referenceto FIGS. 4A-4C, which illustrate a method 400 for determining anormalized set of SINR offset calibrations for a partition based on SINRmeasurements performed by a set of terminals of the partition. Invarious embodiments, method 400 may be performed for a set of satellitepartitions to determine a normalized set of SINR offset calibrations foreach partition.

Method 400 will be described with reference to FIGS. 5-7, which aretables illustrating a particular implementation of method 400 for agroup of 17 terminals that took measurements over a 26-channel frequencyband. The tables list values in units of centibels (cB), i.e. 0.1decibels (dB). It is worth noting that FIGS. 5-7 are provided for thepurpose of illustration only, and are not meant to limit the technologydisclosed herein. In particular, method 400 may be implemented for anynumber of terminals, frequency channels, and partitions. Furthermore,other suitable statistical methodologies may be implemented in place ofthose described with reference to FIGS. 5-7.

With reference now to method 400, at operation or method 400A, the IFCmeasurements made by each terminal are processed to compute normalizedIFC measurements. FIG. 4B illustrates method 400A in greater detail. Atoperation 402 the SINR measurements are used to compute initial IFCstatistics. In one embodiment, the initial IFC statistics are computedby taking the average of the SINR measurements for each channel by eachterminal. At operation 404, for each terminal outliner SINR measurementsat each IFC may be removed from consideration. In one implementation,outliers may be removed if they exceed a predetermined number ofstandard deviations from the average (e.g. 0.5, 1, 1.5, 2, 3, etc.). Inother implementations, outliers may be removed based on theinterquartile range of the measurements.

At operation 406, the IFC statistics are recomputed following theremoval of outliers. In one embodiment, the IFC statistics are computedby taking the average of the SINR measurements for each channel by eachterminal without the outliers. For example, if a terminal made the SINRmeasurements 130 cB, 129 cB, 131 cB, and 180 cB for a given channel,then the 180 cB measurement may be removed (operation 404) to arrive atan average SINR of 130 cB (operation 406). In additional embodiments,operations 404 through 406 may be iteratively repeated to removeoutliers from the recomputed statistics. Alternatively, in otherembodiments operations 404 and 406 may be skipped.

Table 500 of FIG. 5 illustrates an example table of SINR measurementsafter operations 402-406 are performed for a 17 terminal and 26 IFCpartition. As illustrated, each row of table 500 corresponds to aterminal 510 (T₁ through T₁₇), and each column of table 500 correspondsto an IFC 520 (f₁ through f₂₆). Table 500 additionally comprises amaximum SINR column 530 that lists the maximum SINR determined for aterminal 510. For example, for terminal T₅, the maximum SINR is 185 cBas measured on IFC f₂₅. As illustrated by table 500, there may beconsiderable variation in the SINR across different IFC.

At operation 408, for each terminal, the SINR measurements arenormalized. In one embodiment, the SINR measurements are normalized fora given terminal by subtracting the terminal's IFC SINRs from theterminal's maximum IFC SINR, thereby creating normalized SINR offsetsfor each channel. The application of this embodiment is illustrated withreference to FIGS. 5 and 6. Consider terminal T16 as an example. Asshown in table 500, the measured SINRs are 173 cB on IFC f₁₁, 189 cB onIFC f₁₄, and 190 cb on IFC f₂₅. The maximum SINR is 190 cB. As shown intable 600, after normalization based on the highest SINR, the normalizedSINR offsets of these channels are 17 cB, 1 cB, and 0 cB, respectively.

One benefit provided by this normalization operation is that it accountsfor terminals located at various locations with varying antennaattenuations. For example, a terminal located near the edge of asatellite beam will have a lower SINR across all channels as compared toa terminal located near the center of the beam. By performingnormalization operation 408, these two terminals may be compared basedon their SINR offsets.

With reference again to method 400, at operation 400B the normalized IFCmeasurements of each terminal of a partition are processed to computefinal calibrated IFC SINR offsets for each IFC of the partition. FIG. 4Cillustrates method 400B in greater detail. At operation 410, one or moreclear channels are determined based on the normalized SINR offsets. Asused herein, the term “clear channels” refers to the IFCs with thelowest interference levels (highest SINRs) on a frequency band orpartition. In one embodiment, clear channels are determined by selectingthe IFCs with an average SINR offset below a predetermined value. In oneparticular embodiment, an IFC must have an average SINR offset below 1cB to be selected as a clear channel. In implementations of thisembodiment, an IFC is selected as a clear channel only if it has aminimum number of terminals that have measurements on the IFC (e.g. atleast 3 or 4.) In further embodiments, outliers are removed from an IFC's set of SINR offsets prior to determining the average SINR offset forthe IFC.

Table 600 of FIG. 6 illustrates an example table of SINR offsets and IFCstatistics after clear channels are determined. As illustrated, the IFCstatistics of table 600 include for each IFC the sample size 610 (numberof terminals with measurements on that channel), the average SINR offset630, and the standard deviation 620 of the IFC's set of offsets. In thisexample implementation, an IFC is selected as a clear channel if itsaverage SINR offset is below 3 cB and its sample size of measurements isat least 3. In this example, three IFC (f₁₄, f₂₄, and f₂₆) satisfy theclear channel criteria. By comparison, f₄ does not satisfy the criteriaof a clear channel in this example because it only has two samplemeasurements.

At operation 412, terminals without measurements on the clear channelsare removed from consideration. Accordingly, in subsequent operations ofmethod 400 only terminals that have SINR offset values on clear channelsare considered. In table 600, for example, terminals T₅, T₇, T₈, T₁₅,and T₁₇ do not have any measurements on any clear channel. Accordingly,these terminals do not appear in table 700 of FIG. 700, whichillustrates a particular implementation of subsequent operations ofmethod 400.

At operation 414, for each IFC of the partition, outlier terminal SINRoffset samples are removed from consideration. In one implementation ofthis embodiment, the population average SINR offset, i.e. the average ofall SINR offset measurements determined for all terminals for an IFC, iscomputed. Subsequently, any terminal SINR offset that is an outlierrelative to this population average is removed. Consider for example,the implementation where outliers are removed if they exceed 2 standarddeviations. If the population average SINR offset for a given IFC is 4cB and the standard deviation is 1 cB, then terminals with a SINR offsetthat is not between 2 cB and 6 cB will not be considered for that IFC insubsequent operations of method 400B. In alternative embodiments,operation 414 may be skipped.

After the terminals are removed from consideration, and statisticalsample outliers are removed, at operation 416 the IFC statistics arerecomputed to determine the final calibrated IFC SINR offset for eachchannel. In one embodiment, the IFC statistics are recomputed by takingthe means and standard deviations of each IFC's offset SINR values.Table 700 illustrates one such implementation of this embodiment. Asillustrated, the recomputed IFC statistics of table 700 include for eachIFC the sample size 710 (number of terminals with measurements on thatchannel), the average SINR offset 730, and the standard deviation 720 ofthe IFC's set of offsets. Consider IFC f₁₄ as an example. The averageSINR offset of f₁₄ is 1 cB with a standard deviation of 2 cB.

At operation 400C of method 400, the final calibrated IFC SINR offsetsfor each channel of a partition are normalized with respect to a lowestSINR offset IFC. Consider Table 700 as an example. The lowest IFC offsethas a mean of 1 cB. Accordingly, the IFC offsets may be normalized withrespect to 0 by subtracting 1 off all of the means.

In one embodiment, the final calibrated IFC offset for each channel of afrequency band partition may be expressed as Equation (1):Offset_(ifc)=IFC_(mean) +K*IFC_(std)   (1)Where IFC_(mean) is the mean of the IFC's offset SINR values, IFC_(std)is the standard deviation of those values, and K is a constant between 0and 5. In various embodiments, the value of K may be selected dependingon the desired confidence of the SINR offset calibration of thechannels.

Following determination of the calibrated IFC SINR offsets, they may bemade available to the terminals in a suitable format. For example, inone embodiment the IFC SINR offsets may be transmitted to a terminal ina calibration table containing mean and standard deviation SINR offsetsfor each channel of a frequency band the terminal operates on.Accordingly, when transitioning from one IFC to another, a terminal mayaccount for differences in the SINR between the IFC. In furtherembodiments, the calibrated IFC SINR offsets determined for eachpartition may be concatenated into a single file (e.g., a calibrationtable in one file). Alternatively, the calibrated IFC SINR offsetsdetermined for each partition may be transmitted separately (e.g., inseparate calibration tables in separate files).

FIG. 8 is a plot illustrating an example inroute calibration mapping fora satellite beam created by applying the methods disclosed herein. Theplot shows the calibrated offset values in cB as a function offrequency. There are two curves shown for computed calibrated resultsfor data collected on a beam 2 days apart. As illustrated, thecalibration offsets are fairly consistent over the course of a few days.

FIG. 9 is another plot illustrating another example calibration mappingfor another satellite beam created by applying the methods disclosedherein. There are two curves shown for computed calibrated results fordata collected on a beam 4 days apart. As illustrated, the calibrationoffsets are fairly consistent over the course of several days.

FIG. 10 illustrates a computer system 1000 upon which exampleembodiments according to the present disclosure can be implemented.Computer system 1000 can include a bus 1002 or other communicationmechanism for communicating information, and a processor 1004 coupled tobus 1002 for processing information. Computer system 1000 may alsoinclude main memory 1006, such as a random access memory (RAM) or otherdynamic storage device, coupled to bus 1002 for storing information andinstructions to be executed by processor 1004. Main memory 1006 can alsobe used for storing temporary variables or other intermediateinformation during execution of instructions to be executed by processor1004. Computer system 1000 may further include a read only memory (ROM)1008 or other static storage device coupled to bus 1002 for storingstatic information and instructions for processor 1004. A storage device1010, such as a magnetic disk or optical disk, may additionally becoupled to bus 1002 for storing information and instructions.

Computer system 1000 can be coupled via bus 1002 to a display 1012, suchas a cathode ray tube (CRT), liquid crystal display (LCD), active matrixdisplay, light emitting diode (LED)/organic LED (OLED) display, digitallight processing (DLP) display, or plasma display, for displayinginformation to a computer user. An input device 1014, such as a keyboardincluding alphanumeric and other keys, may be coupled to bus 1002 forcommunicating information and command selections to processor 1004.Another type of user input device is cursor control 1016, such as amouse, a trackball, or cursor direction keys for communicating directioninformation and command selections to processor 1004 and for controllingcursor movement on display 1012.

According to one embodiment of the disclosure, satellite noise andinterference calibration, in accordance with example embodiments, areprovided by computer system 1000 in response to processor 1004 executingan arrangement of instructions contained in main memory 1006. Suchinstructions can be read into main memory 1006 from anothercomputer-readable medium, such as storage device 1010. Execution of thearrangement of instructions contained in main memory 1006 causesprocessor 1004 to perform one or more processes described herein. One ormore processors in a multi-processing arrangement may also be employedto execute the instructions contained in main memory 1006. Inalternative embodiments, hard-wired circuitry is used in place of or incombination with software instructions to implement various embodiments.Thus, embodiments described in the present disclosure are not limited toany specific combination of hardware circuitry and software.

Computer system 1000 may also include a communication interface 1018coupled to bus 1002. Communication interface 1018 can provide a two-waydata communication coupling to a network link 1020 connected to a localnetwork 1022. By way of example, communication interface 1018 may be adigital subscriber line (DSL) card or modem, an integrated servicesdigital network (ISDN) card, a cable modem, or a telephone modem toprovide a data communication connection to a corresponding type oftelephone line. As another example, communication interface 1018 may bea local area network (LAN) card (e.g. for Ethernet™ or an AsynchronousTransfer Model (ATM) network) to provide a data communication connectionto a compatible LAN. Wireless links can also be implemented. In any suchimplementation, communication interface 1018 sends and receiveselectrical, electromagnetic, or optical signals that carry digital datastreams representing various types of information. Further,communication interface 1018 may include peripheral interface devices,such as a Universal Serial Bus (USB) interface, a PCMCIA (PersonalComputer Memory Card International Association) interface, etc.

Network link 1020 typically provides data communication through one ormore networks to other data devices. By way of example, network link1020 can provide a connection through local network 1022 to a hostcomputer 1024, which has connectivity to a network 1026 (e.g. a widearea network (WAN) or the global packet data communication network nowcommonly referred to as the “Internet”) or to data equipment operated byservice provider. Local network 1022 and network 1026 may both useelectrical, electromagnetic, or optical signals to convey informationand instructions. The signals through the various networks and thesignals on network link 1020 and through communication interface 1018,which communicate digital data with computer system 1000, are exampleforms of carrier waves bearing the information and instructions.

Computer system 1000 may send messages and receive data, includingprogram code, through the network(s), network link 1020, andcommunication interface 1018. In the Internet example, a server (notshown) might transmit requested code belonging to an application programfor implementing an embodiment of the present disclosure through network1026, local network 1022 and communication interface 1018. Processor1004 executes the transmitted code while being received and/or store thecode in storage device 1010, or other non-volatile storage for laterexecution. In this manner, computer system 1000 obtains application codein the form of a carrier wave.

The term “computer-readable medium” as used herein refers to any mediumthat participates in providing instructions to processor 1004 forexecution. Such a medium may take many forms, including but not limitedto non-volatile media, volatile media, and transmission media.Non-volatile media include, for example, optical or magnetic disks, suchas storage device 1010. Volatile media may include dynamic memory, suchas main memory 1006. Transmission media may include coaxial cables,copper wire and fiber optics, including the wires that comprise bus1002. Transmission media can also take the form of acoustic, optical, orelectromagnetic waves, such as those generated during radio frequency(RF) and infrared (IR) data communications. Common forms ofcomputer-readable media include, for example, a floppy disk, a flexibledisk, hard disk, magnetic tape, any other magnetic medium, a CD ROM,CDRW, DVD, any other optical medium, punch cards, paper tape, opticalmark sheets, any other physical medium with patterns of holes or otheroptically recognizable indicia, a RAM, a PROM, and EPROM, a FLASH EPROM,any other memory chip or cartridge, a carrier wave, or any other mediumfrom which a computer can read.

Various forms of computer-readable media may be involved in providinginstructions to a processor for execution. By way of example, theinstructions for carrying out at least part of the present disclosuremay initially be borne on a magnetic disk of a remote computer. In sucha scenario, the remote computer loads the instructions into main memoryand sends the instructions over a telephone line using a modem. A modemof a local computer system receives the data on the telephone line anduses an infrared transmitter to convert the data to an infrared signaland transmit the infrared signal to a portable computing device, such asa personal digital assistance (PDA) and a laptop. An infrared detectoron the portable computing device receives the information andinstructions borne by the infrared signal and places the data on a bus.The bus conveys the data to main memory, from which a processorretrieves and executes the instructions. The instructions received bymain memory may optionally be stored on storage device either before orafter execution by processor.

FIG. 11 illustrates a chip set 1100 in which embodiments of thedisclosure may be implemented. Chip set 1100 can include, for instance,processor and memory components described with respect to FIG. 11incorporated in one or more physical packages. By way of example, aphysical package includes an arrangement of one or more materials,components, and/or wires on a structural assembly (e.g., a baseboard) toprovide one or more characteristics such as physical strength,conservation of size, and/or limitation of electrical interaction.

In one embodiment, chip set 1100 includes a communication mechanism suchas a bus 1002 for passing information among the components of the chipset 1100. A processor 1104 has connectivity to bus 1102 to executeinstructions and process information stored in a memory 1106. Processor1104 includes one or more processing cores with each core configured toperform independently. A multi-core processor enables multiprocessingwithin a single physical package. Examples of a multi-core processorinclude two, four, eight, or greater numbers of processing cores.Alternatively or in addition, processor 1104 includes one or moremicroprocessors configured in tandem via bus 1102 to enable independentexecution of instructions, pipelining, and multithreading. Processor1004 may also be accompanied with one or more specialized components toperform certain processing functions and tasks such as one or moredigital signal processors (DSP) 1108, and/or one or moreapplication-specific integrated circuits (ASIC) 1110. DSP 1108 cantypically be configured to process real-world signals (e.g., sound) inreal time independently of processor 1104. Similarly, ASIC 1110 can beconfigured to performed specialized functions not easily performed by ageneral purposed processor. Other specialized components to aid inperforming the inventive functions described herein include one or morefield programmable gate arrays (FPGA) (not shown), one or morecontrollers (not shown), or one or more other special-purpose computerchips.

Processor 1104 and accompanying components have connectivity to thememory 1106 via bus 1102. Memory 1106 includes both dynamic memory(e.g., RAM) and static memory (e.g., ROM) for storing executableinstructions that, when executed by processor 1104, DSP 1108, and/orASIC 1110, perform the process of example embodiments as describedherein. Memory 1106 also stores the data associated with or generated bythe execution of the process.

As used herein, the term module might describe a given unit offunctionality that can be performed in accordance with one or moreembodiments of the present application. As used herein, a module mightbe implemented utilizing any form of hardware, software, or acombination thereof. For example, one or more processors, controllers,ASICs, PLAs, PALs, CPLDs, FPGAs, logical components, software routinesor other mechanisms might be implemented to make up a module. Inimplementation, the various modules described herein might beimplemented as discrete modules or the functions and features describedcan be shared in part or in total among one or more modules. In otherwords, as would be apparent to one of ordinary skill in the art afterreading this description, the various features and functionalitydescribed herein may be implemented in any given application and can beimplemented in one or more separate or shared modules in variouscombinations and permutations. Even though various features or elementsof functionality may be individually described or claimed as separatemodules, one of ordinary skill in the art will understand that thesefeatures and functionality can be shared among one or more commonsoftware and hardware elements, and such description shall not requireor imply that separate hardware or software components are used toimplement such features or functionality.

Where components or modules of the application are implemented in wholeor in part using software, in one embodiment, these software elementscan be implemented to operate with a computing or processing modulecapable of carrying out the functionality described with respectthereto. One such example computing module is shown in FIG. 10. Variousembodiments are described in terms of this example-computing module1000. After reading this description, it will become apparent to aperson skilled in the relevant art how to implement the applicationusing other computing modules or architectures.

Although described above in terms of various exemplary embodiments andimplementations, it should be understood that the various features,aspects and functionality described in one or more of the individualembodiments are not limited in their applicability to the particularembodiment with which they are described, but instead can be applied,alone or in various combinations, to one or more of the otherembodiments of the present application, whether or not such embodimentsare described and whether or not such features are presented as being apart of a described embodiment. Thus, the breadth and scope of thepresent application should not be limited by any of the above-describedexemplary embodiments.

Terms and phrases used in the present application, and variationsthereof, unless otherwise expressly stated, should be construed as openended as opposed to limiting. As examples of the foregoing: the term“including” should be read as meaning “including, without limitation” orthe like; the term “example” is used to provide exemplary instances ofthe item in discussion, not an exhaustive or limiting list thereof; theterms “a” or “an” should be read as meaning “at least one,” “one ormore” or the like; and adjectives such as “conventional,” “traditional,”“normal,” “standard,” “known” and terms of similar meaning should not beconstrued as limiting the item described to a given time period or to anitem available as of a given time, but instead should be read toencompass conventional, traditional, normal, or standard technologiesthat may be available or known now or at any time in the future.Likewise, where this document refers to technologies that would beapparent or known to one of ordinary skill in the art, such technologiesencompass those apparent or known to the skilled artisan now or at anytime in the future.

The use of the term “module” does not imply that the components orfunctionality described or claimed as part of the module are allconfigured in a common package. Indeed, any or all of the variouscomponents of a module, whether control logic or other components, canbe combined in a single package or separately maintained and can furtherbe distributed in multiple groupings or packages or across multiplelocations.

Additionally, the various embodiments set forth herein are described interms of exemplary block diagrams, flow charts and other illustrations.As will become apparent to one of ordinary skill in the art afterreading this document, the illustrated embodiments and their variousalternatives can be implemented without confinement to the illustratedexamples. For example, block diagrams and their accompanying descriptionshould not be construed as mandating a particular architecture orconfiguration.

What is claimed is:
 1. A system, comprising: one or more processors; andone or more non-transitory computer-readable mediums operatively coupledto at least one of the one or more processors and having instructionsstored thereon that, when executed by at least one of the one or moreprocessors, cause the system to: receive a plurality of signal tointerference-plus-noise ratio (SINR) measurements made by a plurality ofterminals for a plurality of inroute frequency channels (IFCs);normalize the SINR measurements for each of the plurality of terminals,wherein normalizing the SINR measurements for each of the plurality ofterminals comprises: for each of the plurality of terminals: determininga difference between each of the terminal's IFC SINR measurements andthe terminal's maximum IFC SINR measurement, thereby creating normalizedSINR offsets for each IFC; determine one or more clear channels of theplurality of IFC using at least the normalized SINR measurements; anddetermine a final calibrated IFC SINR offset for each of the pluralityof IFCs.
 2. A system, comprising: one or more processors; and one ormore non-transitory computer-readable mediums operatively coupled to atleast one of the one or more processors and having instructions storedthereon that, when executed by at least one of the one or moreprocessors, cause the system to: compute initial statistics for aplurality of signal to interference-plus-noise ratio (SINR) measurementsmade by a plurality of terminals for a plurality of inroute frequencychannels (IFCs); normalize the SINR measurements for each of theplurality of terminals; determine one or more clear channels of theplurality of IFC using at least the normalized SINR measurements; anddetermine a final calibrated IFC SINR offset for each of the pluralityof IFCs, wherein the final calibrated IFC SINR offset for each IFC isdetermined by Offset_(ifc)=IFC_(mean)+K₆*IFC_(std), wherein IFC_(mean)is a mean of the IFC's offset SINR values, IFC_(std) is the standarddeviation of the values, and K is a constant between 0 and
 5. 3. Thesystem of claim 1, wherein the instructions when executed by at leastone of the one or more processors, further cause the system to: computeinitial statistics for the plurality of SINR measurements made by theplurality of terminals for the plurality IFCs, wherein computing theinitial statistics comprises taking an average of SINR measurements madefor each of the plurality of IFCs by each of the plurality of terminals.4. The system of claim 1, wherein the instructions when executed by atleast one of the one or more processors, further cause the system to:remove outlier SINR measurements for each of the plurality of terminalsfor each IFC.
 5. The system of claim 4, wherein removing outlier SINRmeasurements for each of the plurality of terminals for each IFCcomprises: determining an average SINR measurement of the IFC by theterminal; and removing any SINR samples by the terminal that are morethan a predetermined number of standard deviations away from the averageSINR.
 6. The system of claim 1, further comprising: a satellite gatewayconfigured to receive the plurality of SINR measurements made by theplurality of terminals.
 7. A method comprising: receiving over acommunications network a plurality of signal to interference-plus-noiseratio (SINR) measurements made by a plurality of terminals for aplurality of inroute frequency channels (IFCs); normalizing the SINRmeasurements for each of the plurality of terminals, wherein normalizingthe SINR measurements for each of the plurality of terminals comprises:for each of the plurality of terminals: determining a difference betweeneach of the terminal's IFC SINR measurements and the terminal's maximumIFC SINR measurement, thereby creating normalized SINR offsets for eachIFC; determining one or more clear channels of the plurality of IFCsusing at least the normalized SINR measurements; and determining a finalcalibrated IFC SINR offset for each of the plurality of IFCs.
 8. Themethod of claim 7, wherein the final calibrated IFC SINR offset for eachof the plurality of IFCs is determined byOffset_(ifc)=IFC_(mean)+K₆*IFC_(std), wherein IFC_(mean)is a mean of theIFC's offset SINR values, IFC_(std) is the standard deviation of thevalues, and K is a constant between 0 and
 5. 9. The method of claim 7,further comprising: computing initial statistics for the plurality ofSINR measurements, wherein computing the initial statistics comprisestaking an average of SINR measurements made for each of the plurality ofIFCs by each of the plurality of terminals.
 10. The system of claim 6,wherein the satellite gateway is configured to determine the clearchannels of the plurality of IFC.
 11. The system of claim 4, wherein theinstructions when executed by at least one of the one or moreprocessors, further cause the system to: after removing the outlier SINRmeasurements for each of the plurality of terminals for each IFC,compute an average of SINR measurements made for each of the pluralityof IFCs by each of the plurality of terminals without the outlier SINRmeasurements.
 12. The system of claim 1, wherein the one or more clearchannels are determined using at least the normalized SINR offsets foreach IFC.
 13. The system of claim 12, wherein the one or more clearchannels are determined by selecting IFCs with an average SINR offsetbelow a predetermined threshold.
 14. The system of claim 13, wherein theone or more clear channels are determined by selecting IFCs with anaverage SINR offset below a predetermined threshold and having at leasta minimum number of terminals with SINR measurements on the channel. 15.The system of claim 12, further comprising: transmitting, to theplurality of terminals, the final calibrated IFC SINR offsets for eachof the plurality of IFCs the plurality of terminals operate on.
 16. Thesystem of claim 15, wherein the final calibrated IFC SINR offsets foreach of the plurality of IFCs are transmitted in a calibration table.17. The system of claim 1, wherein the instructions when executed by atleast one of the one or more processors, further cause the system to:remove from consideration SINR measurements made by each of theplurality of terminals without SINR measurements on at least one of theone or more clear channels.
 18. The method of claim 7, wherein theplurality of SINR measurements made by the plurality of terminals arereceived by a satellite gateway over the communications network, whereinthe satellite gateway determines the final calibrated IFC SINR offsetfor each of the plurality of IFCs.
 19. The method of claim 7, furthercomprising: removing outlier SINR measurements for each of the pluralityof terminals for each IFC.
 20. The method of claim 19, wherein removingoutlier SINR measurements for each of the plurality of terminals foreach IFC comprises: determining an average SINR measurement of the IFCby the terminal; and removing any SINR samples by the terminal that aremore than a predetermined number of standard deviations away from theaverage SINR measurement.
 21. The method of claim 20, furthercomprising: after removing the outlier SINR measurements for each of theplurality of terminals for each IFC, computing an average of SINRmeasurements made for each of the plurality of IFCs by each of theplurality of terminals without the outlier SINR measurements.
 22. Themethod of claim 7 wherein the one or more clear channels are determinedusing at least the normalized SINR offsets for each IFC.
 23. The methodof claim 22, wherein the one or more clear channels are determined byselecting IFCs with an average SINR offset below a predeterminedthreshold.
 24. The method of claim 23, wherein the one or more clearchannels are determined by selecting IFCs with an average SINR offsetbelow a predetermined threshold and having at least a minimum number ofterminals with SINR measurements on the channel.
 25. The method of claim22, further comprising: transmitting, to the plurality of terminals, thefinal calibrated IFC SINR offsets for each of the plurality of IFCs theplurality of terminals operate on.
 26. The method of claim 25, whereinthe final calibrated IFC SINR offsets for each of the plurality of IFCsare transmitted in a calibration table.
 27. The method of claim 7,further comprising: removing from consideration SINR measurements madeby each of the plurality of terminals without SINR measurements on atleast one of the one or more clear channels.
 28. A method, comprising: asatellite gateway instructing a plurality of terminals over an outroutechannel to measure a signal to interference-plus-noise ratio (SINR) of aplurality of inroute frequency channels (IFCs) corresponding to asatellite network partition; in response to the instruction, thesatellite gateway receiving over an inroute channel a plurality of SINRmeasurements made by the plurality of terminals for the plurality ofIFCs; the satellite gateway normalizing the SINR measurements for eachof the plurality of terminals, wherein normalizing the SINR measurementsfor each of the plurality of terminals comprises: for each of theplurality of terminals: determining a difference between each of theterminal's IFC SINR measurements and the terminal's maximum IFC SINRmeasurement, thereby creating normalized SINR offsets for each IFC thesatellite gateway determining a final calibrated IFC SINR offset foreach of the plurality of IFCs; and transmitting, to the plurality ofterminals, the final calibrated IFC SINR offsets.